will SBS2008 backup overwrite older backup files

I am using a single external 1TGB USB drive as a secondary backup system for my SBS2008 server. I have set it to backup the 360GB mirrored 'C' drive each day. The data drive is another mirror pair being backed up by other methods. Will the USB drive eventually fill up or does it just overwrite the changed blocks thus meaning I can connect & not worry about drive filling up. (users data will be on the other drive)

Interesting question.
You probably already saw this link:http://blogs.technet.com/b/sbs/archive/2008/11/03/introducing-sbs-2008-backup.aspx
At the backup time, there are written only changed blocks. And the older blocks are retained with metadata.
So theoreticly you should run out of place sooner or later. I did not noticed anywhere an option to set for how long the old data is kept. So I PRESUME that backup has some sort of mechanism, that when the backup disk runs out of space, that the oldest blocks are overwritten.
As you have backup disk big enough (2,5 times of size of backed up data), you will need quite some time to figure that out ;)

Featured Post

Manage projects of all sizes how you want. Great for personal to-do lists, project milestones, team priorities and launch plans.
- Combine task lists, docs, spreadsheets, and chat in one
- View and edit from mobile/offline
- Cut down on emails

Introduction
At 19:33 (UST) on Tuesday 21st September the long awaited email arrived with the subject title of “ANNOUNCING THE AVAILABILITY OF WINDOWS SBS 7 PREVIEW”. It was time to drop whatever I was doing and dedicate as much bandwidth as possi…

The articles for turning off the Client firewall policy on the internet are for SBS 2008 and don't really help for SBS 2011. They actually moved the Client firewall policy.
In 2011, the client firewall policy has moved to the SBS computers conta…

When you create an app prototype with Adobe XD, you can insert system screens -- sharing or Control Center, for example -- with just a few clicks. This video shows you how. You can take the full course on Experts Exchange at http://bit.ly/XDcourse.